A FEA simulation study of ball end mill for fixed 3+1 / 3+2 axis machining of Ti-6Al-4V

Abstract

This paper presents a Finite Element Analysis (FEA) simulation study conducted on ball endmill for fixed 3 + 1 and 3 + 2 axis orientations for machining Ti-6Al-4 V. This work adopts a tungsten carbide (WC) Ø18.6 mm diametrical/6fluted ball endmill to analyse maximum principal elastic strain (εmax-max-principal-elastic), maximum principal stress (σmax-principal) along with cutting tools forces in the axial (Fz), radial (Fy), tangential (Fx) and total (Ftotal) directions. The machining orientations considered for 3 + 1 and 3 + 2 axis are (i) tilt angles of 5°, 10°, 15° & 20° and (ii) lead angles of 5°, 10° & 15° with a constant fixed tilt angle of 10°. The cutting speed and feed rate per tooth is taken as 450 m/min and 0.5 mm/tooth. These are based on a high speed machining (HSM) scenario and has been dynamically simulated for a maximum of 175,000 cycles. From the simulation study considered at 16–20 valid cutting points, it can be noticed that in 3 + 1 axis, for a tilt angle of 10° and 3 + 2 axis for a Tilt 10°/Lead 10° the σmax-principal and εmax-max-principal-elastic are higher when compared with all tilt/lead angles. In case of total forces (Ftotal) from all 3 directions (Fx, Fy and Fz) not much variation can be noticed for different tilt/lead angles, but higher values are recorded with 3 + 1 axis at 5° tilt angle and 3 + 2 axis at tilt/lead angle of 10°. The paper provides a critical comparative study on the 3 + 1/ 3 + 2 axis orientations highlighting the cutting strain/stress with tool forces at valid cutting points considering entry, middle and exit region of the blank by emphasizing the importance of cutting tool design parameters.